Interferon-induced enzyme activities, such as the oligo (2'yields 5') adenylate synthetase and the 67K protein kinase, are investigated with a goal of understanding their role in the action of interferon, the induction of interferon by double-stranded RNA (dsRNA) and, perhaps, control of cell-growth and differentiation. A new assay for the oligo (2'yields 5') adenylate synthetase has been developed and this has permitted the beginning of a study of the ability of differently modified dsRNA's and nucleic acids to activate this enzyme from mouse L cells. A similar study is being conducted with 67K protein kinase activity from extracts of mouse L cells. Evidence has been gathered that suggests the importance of a cellular phosphatase activity in determining the net labeling of the 67K protein by gamma-32P-ATP.